And the Electoral Reform Society for Scotland says its findings have given fresh impetus to calls for the introduction of proportional representation.
The body wants to see changes to the existing first past the post system for the Westminster elections.
Proportional representation has already been introduced north of the Border in the elections for the Scottish Parliament.
" Our antiquated voting system has failed the voters of Scotland yet again "
Dr James Gilmour
Proposals to adopt a system of PR in local council elections are also before the Scottish Parliament.
The Electoral Reform Society for Scotland said half of Scotland's 72 MPs were elected even though more electors voted against them than for them - compared to 30 at the last general election.
It also said that Labour had taken 78% of the Scottish seats with just 44% of the votes, while the third largest party, the Liberal Democrats, won twice as many seats as the Scottish National Party - which polled 100,000 more votes.
"However, the real losers were the voters. They did not get the representatives they wanted," said spokesman Dr James Gilmour.
"Our antiquated voting system has failed the voters of Scotland yet again.
"There is little incentive to vote if the system is just going to waste the votes and deny so many voters any say in the result."